Palmu Arto A, Rinta-Kokko Hanna, Nohynek Hanna, Nuorti J Pekka, Kilpi Terhi M, Jokinen Jukka
Department of Public Health Solutions, National Institute for Health and Welfare, Tampere, Finland.
Department of Public Health Solutions, National Institute for Health and Welfare, Helsinki, Finland.
PLoS One. 2017 Mar 1;12(3):e0172690. doi: 10.1371/journal.pone.0172690. eCollection 2017.
The ten-valent pneumococcal conjugate vaccine (PCV10) was introduced into the Finnish National Vaccination Program (NVP) in September 2010 using a 2+1 schedule (3, 5, 12 months). We estimated the direct and indirect effects of PCV10 on pneumonia among children to evaluate the public health impact of the vaccine.
We conducted a nation-wide population-based, observational study comparing rates of pneumonia in children before and after the NVP introduction. For the total (direct and indirect) effect, the cohort of vaccine-eligible children (born June 1, 2010 or later) was followed until the end of 2013 (age range 3-42 months). For the indirect effect, a cohort of older children (age range 7-71 months) not eligible for the PCV vaccination was followed from 2011 to 2013. Both cohorts were compared with two season- and age-matched reference cohorts before NVP introduction. Hospitals' in- and outpatient discharge notifications with ICD-10 diagnoses compatible with pneumonia (J10.0, J11.0, J12-J18, J85.1 or J86) as set by the hospital pediatricians were collected from the national Care Register. The main outcome was hospital-treated primary pneumonia (HTPP), defined as primary diagnosis of pneumonia after in-patient hospitalization. We compared rates of pneumonia in the NVP target and reference cohorts by using Poisson regression models.
The rate of HTPP episodes was 5.3/1000 person-years in the combined reference cohorts and 4.1/1000 person-years in the target cohort vaccine-eligible children. Compared with the reference cohort, the relative rate reduction in target cohort was 23% (95%CI 18-28) and the absolute reduction 1.3/1000 person-years. In the indirect effect evaluation, we observed continued increase in HTPP incidence until 2011 with a subsequent reduction of 18% (95%CI 10-25) during years 2012 to 2013. Number of empyema diagnoses remained low.
A substantial decrease in pneumonia rates was observed both among vaccine-eligible children and among older, unvaccinated children after PCV10 introduction.
十价肺炎球菌结合疫苗（PCV10）于2010年9月采用2+1免疫程序（3、5、12月龄）纳入芬兰国家疫苗接种计划（NVP）。我们评估了PCV10对儿童肺炎的直接和间接影响，以评价该疫苗对公共卫生的影响。
我们开展了一项基于全国人群的观察性研究，比较了NVP实施前后儿童肺炎的发病率。对于总体（直接和间接）影响，对符合疫苗接种条件的儿童队列（2010年6月1日及以后出生）进行随访至2013年底（年龄范围3 - 42月龄）。对于间接影响，对不符合PCV疫苗接种条件的大龄儿童队列（年龄范围7 - 71月龄）在2011年至2013年进行随访。两个队列均与NVP实施前两个季节和年龄匹配的参照队列进行比较。从国家医疗保健登记处收集医院儿科医生按照国际疾病分类第十版（ICD - 10）诊断标准（J10.0、J11.0、J12 - J18、J85.1或J86）诊断为肺炎的住院和门诊出院通知。主要结局为医院治疗的原发性肺炎（HTPP），定义为住院后肺炎的初步诊断。我们使用泊松回归模型比较了NVP目标队列和参照队列中的肺炎发病率。
合并参照队列中HTPP发病率为5.3/1000人年，目标队列中符合疫苗接种条件的儿童发病率为4.1/1000人年。与参照队列相比，目标队列中相对发病率降低了23%（95%CI 18 - 28），绝对降低了1.3/1000人年。在间接影响评估中，我们观察到HTPP发病率在2011年之前持续上升，随后在2012年至2013年期间下降了18%（95%CI 10 - 25）。脓胸诊断数量仍然较低。
在引入PCV10后，符合疫苗接种条件的儿童以及未接种疫苗的大龄儿童中肺炎发病率均显著下降。
